Automatic choke heater



Oct. 19, 1965 w. N. LORGE 3,212,486

AUTOMATIC CHOKE HEATER Filed 001;. 22, 1962 2 Sheets-Sheet 1 Walter M Large 1 N VE N TOR.

Oct. 19, 1965 w. N. LORGE 3,212,486

AUTOMATIC CHOKE HEATER Filed 001;. 22, 1962 2 Sheets-Sheet 2 Fig. 4

Walter IV. Large I INVENTOR.

United States Patent 3,212,486 AUTOMATIC CHOKE HEATER Walter N. Lorge, 2633 Oakland Ave., Waukegan, Ill. Filed Oct. 22, 1962, Ser. No. 232,208 6 Claims. (Cl. 123-119) This invention relates to a novel and useful automatic choke heater and more specifically to a heater designed primarily for the purpose of rapidly heating the bimetallic member of an automatic choke assembly.

Internal combustion engines are as a general rule provided with carburetors having automatic choke assemblies that are actuated by means of bimetallic members. Normally, the bimetallic member is enclosed within a casing mounted on the carburetor and the interior of the casing is in communication with a heat conducting tube receiving air treated by the exhaust manifold of the internal combustion engine. As soon as the internal combustion engine is started, assuming that it is cold and that the automatic choke assembly has been actuated, warm air moves up through an insulated conduit and into the casing of the automatic choke assembly in which the bimetallic member is disposed. After a certain length of time, the bimetallic member in the casing is heated and the spring tension effected thereby on the choke is reduced until the return spring or vacuum control of the choke renders the choke completely inoperative. By this time, the internal combustion engine has warmed up to the point that the intake manifold and carburetor have also been warmed sufiiciently to enable the liquid fuel to be properly vaporized.

However, in unseasonably cold weather, the fan of an internal combustion engine passes large quantities of frigid air over the external surfaces of the motor. While this does not appreciably reduce the operating temperature of the motor, it does greatly reduce the amount of water which is passed through the radiator of the engine. Consequently, the cooling air, although being utilized to cool the external surfaces of the internal combustion engine, picks up very little heat on its passage through the engine compartment. Therefore, the exposed surfaces of the internal combustion engine remain quite cold. In these instances, the small amount of heat which is allowed to pass upwardly from the exhaust manifold and through the conduit into the casing enclosing the bimetallic member of an automatic choke assembly is appreciably reduced. Although the base of the carburetor in which area the liquid fuel is vaporized is warmed sufficiently and the intake manifold is also warmed to a point at which the liquid fuel may be properly vaporized, there usually is not a sufficient amount of heat passing upwardly through the conduit and to the bimetallic member in order to deactivate the automatic choke assembly in a reasonable amount of time. Accordingly, in extremely cold weather, the choke assemblies of many carburetors mounted on internal combustion engines are not rendered inoperative as soon as they might be or should be and therefore, fuel economy is greatly affected.

Accordingly, it is the main object of this invention to provide an automatic choke heater for use in connection with an internal combustion engine including an exhaust manifold and an intake manifold having a carburetor mounted thereon provided with an automatic choke assembly actuated by means of a heat response bimetallic member enclosed within a casing carried by the carburetor which automatic choke heater will be operative for properly heating the bimetallic member of the automatic choke assembly after an internal combustion engine has been operating for a period of time sufiicient to heat the areas of the fuel induction system in which the fuel is to be vaporized.

3,212,486 Patented Oct. 19, 1965 "ice Another object of the invention is to provide an automatic choke heater including means by which the amount of heat delivered thereby to supplement the heating of the automatic choke may be adjusted as desired.

A further object of this invention, in accordance with the immediately preceding object, is to provide an automatic choke heater which will be constructed in a manner so as to properly supplement the conventional exhaust heating of the bimetallic member of an automatic choke assembly.

Still another object of this invention is to provide an automatic choke heater in accordance with the preceding objects which will be automatically rendered inoperative as soon as the conventional means for heating the bimetallic member by means of engine exhaust is producing sufficient heat to render the choke assembly inoperative.

A final object of this invention, to be specifically enumerated herein, is to provide an automatic choke heater in accordance with the preceding objects which will conform to conventional forms of manufacture, be of simple construction and easy to install so as to provide a device that will be economically feasible, long lasting and relatively trouble free.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a fragmentary side elevational view of the air and fuel induction system of a conventional type of internal combustion engine shown with the automatic choke feature of the instant invention operatively associated therewith;

FIGURE 2 is a fragmentary elevational view of the embodiment illustrated in FIGURE 1 as seen from the right side thereof;

FIGURE 3 is an enlarged transverse sectional view taken substantially upon the plane indicated by the section line 33 of FIGURE 1;

FIGURE 4 is an enlarged fragmentary sectional view taken substantially upon a plane passing through the longitudinal center line of the housing of the heater; and

FIGURE 5 is a fragmentary sectional view similar to that of FIGURE 4 but showing the thermostatic control switch of the choke heater in a different position of operation.

Referring now more specifically to the drawings the numeral 10 generally designates the engine block of a conventional type of internal combustion engine having an intake manifold 12 and an exhaust manifold 14 mounted on one side thereof with a carburetor 16 mounted atop the intake manifold 12. The carburetor 16 is provided with an automatic choke assembly generally referred to by the reference numeral 18 which is conventional in design and which includes a bimetallic member (not shown) for actuating the choke assembly. The choke assembly 18 includes a casing generally referred to by the reference numeral 20 in which the bimetallic member is disposed. The casing 20 includes an inlet 22 with which one end of a heat conducting tube 24 is connected. The other end of the heat conducting tube 24 is passed through the interior of the exhaust manifold 14.

The preceding description is to be understood as conventional and the automatic choke heater of the instant invention will be described hereinafter.

The automatic choke heater of the instant invention is generally referred to by the reference numeral 26 and includes an elongated housing 28 which is cylindrical and is provided with diametrically reduced opposite ends 30 and 32. From the drawings it may be seen that the housing 28 is disposed in the heat tube or conduit 24 and closely adjacent the casing 20.

The housing 28 is covered with a covering of heat insulating material 34 and has a first terminal 36 insulatively secured therethrough by means of a dielectric grommet 38. The first terminal 36 is disposed adjacent the inlet end of the housing 28 and it may be seen that a second terminal 40 is secured through the housing 28 by means of a dielectric grommet 42 and adjacent the outlet end of the housing 28.

The inner end of the second terminal 40 terminates at 44 and it will be seen that the second terminal 40 is adjustable inwardly of the housing 28 for a purpose to be hereinafter more fully set forth.

One end 46 of a resistance heating coil 48 is secured to the inner end of the terminal 36 and the other end 50 of the coil 48 is secured to the inner end of the second terminal 40. The coil 48 is wound about a dielectric rod-like member 52 which extends longitudinally of the housing 28.

A third terminal 54 is also secured through the outlet end of the housing 28 by means of a dielectric grommet 56 and has one end of a bimetallic strip 58 secured to the inner end thereof. The free end of the bimetallic strip 58 carries a contact 60 which is engageable with the terminal inner end 44 of the second contact 40 as will be more fully set forth hereinafter.

With attention now directed to FIGURE 1 of the drawings there will be seen an electrical circuit generally referred to by the reference numeral 62. The electrical circuit 62 includes a first conductor 64 which has one end secured to a terminal 66 that is electrically connected to the battery 68 by means of the vacuum switch 70. The other end of the first conductor 64 is secured to the outer end of the first terminal 36. The circuit 62 also includes a second conductor 72 and one end of the second conductor 72 is secured to the third terminal 54 while the other end of the conductor 72 is secured to a suitable ground terminal 74 thereby completing the circuit to the battery 68 which is provided with a ground '76. Accordingly, it may be seen that the coil 48 is disposed in series in the circuit 62 including the conductors 64 and 72.

In operation, as soon as the combustion engine is started, current flows through the heating coil 48. As the exhaust from the internal combustion engine 10 passes outwardly through the exhaust manifold 14, the air passing through the heat conducting tube 24 is heated. Upon the passing of this heated air through the housing 28, the heated air is further heated by means of the heating coil 48. The twice heated air then passes into the casing whereupon the bimetallic member (not shown) controlling the automatic choke asembly 18 is slowly heated. After the heated air enters the casing 20 it is drawn into the intake manifold 12 by means of the reduced pressure in the latter.

After a given period of time, suflicient heat will have reached the bimetallic member in the choke assembly 18 to render the automatic choke assembly 18 inoperative. At this point, the portions of the air induction system of the internal combustion engine 10 are sufiiciently heated to provide ample vaporization of the liquid fuel handled by the carburetor 16. At some later time, the heat of the air passing into the housing 28 will raise the temperature of the bimetallic strip 58 an amount sufiicient to cause the contact 60 to move from engagement with the enlarged end portion 44 of the second contact 40 whereupon the circuit 62 will be opened causing cyclic operation of the automatic choke heater 26 until the temperature of the engine 10 and engine compartment is high enough to keep the circuit 62 open.

Inasmuch as the second contact 40 may be adjusted inwardly of the housing 28, the temperature level within the housing 28 which is suflicient to open the circuit 62 may be selected by adjusting the second contact 40.

Further, as the operation of the automatic choke heater is completely automatic and its operation ceases after sufiicient heat is being supplied to the automatic choke assembly 18 by means of the exhaust gases alone, the automatic choke heater 26 will be actuated only when it is needed. Still further, as the automatic choke heater 26 will supply a greater amount of heat to the choke assembly 18 is a shorter period of time, the automatic choke may be set slightly richer than normal to facilitate easier and quicker starting in cold weather, the extra heat provided by the automatic choke heater 26 will be more than enough to offset the extra amount of heat required for deactivation of the choke assembly 18 in the desired amount of time.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. In combination with an internal combustion engine including an exhaust manifold, an intake manifold, a carburetor mounted on said intake manifold and provided with an automatic choke assembly actuated by means of a heat responsive bimetallic member enclosed within a casing including an inlet opening, and a heated air conducting tube having one end communicated with said inlet opening, the other end of said tube being open and disposed in good heat transfer relation with said exhaust manifold, a choke assembly heater attachment comprising a housing having an inlet and an outlet and disposed in said tube between said casing inlet and said exhaust manifold, electrical conductor means having one end electrically connected to engine operation responsive switch means and the other end electrically connected to a suitable ground, a portion of said conductor means being disposed in said housing and having an electrical resistance heating element serially connected therein, and adjustable thermostatic control switch means disposed in said portion of said conductor means for controlling the circuit defined thereby and closing the latter in response to a drop in temperature of the atmosphere within said housing below a predetermined level and opening said circuit in response to a rise in temperature of the atmosphere within said housing above a predetermined point above said predetermined level.

2. The combination of claim 1 wherein said electrical resistance heating element comprises a coil of resistance wire coiled about a rod-like member constructed of dielectric material.

3. The combination of claim 1 wherein said housing is in the form of an elongated cylindrical member having diametrically reduced opposite ends in which said inlet and said outlet are formed, said electrical resistance heating element comprising a coil of resistance wire coiled about a rod-like member constructed of dielectric material, said rod-like member extending longitudinally of said cylindrical member.

4. The combination of claim 1 wherein said housing has a pair of terminals insulatively secured therethrough, the opposite end portions of said portion conductor means being secured to said terminals inwardly of said housing, said engine including an ignition system, one of said terminals being electrically connected to said ignition system, the other of said terminals being adjustable inwardly of said housing from the exterior thereof, said thermostatic control switch including a contact movable into and out of contact with the inner end of said other terminal and electrically connected to a third terminal insulatively secured through said housing, said third terminal being electrically connected to said ground.

5. The combination of claim 1 wherein said housing includes a covering of heat insulative material, said electrical resistance heating element comprising a coil of resistance wire coiled about a rod-like member constructed of dielectric material.

6. The combination of claim 1 wherein said housing has a pair of terminals insulatively secured therethrough, the opposite end portions of said portion conductor means being secured to said terminals inwardly of said housing, said engine including an ignition system, one of said terminals being electrically connected to said ignition system, the other of said terminals being adjustable inwardly of said housing from the exterior thereof, said thermostatic control switch including a contact movable into and out of contact with the inner end of said other terminal and electrically connected to a third terminal insulatively secured through said housing, said third terminal being electrically connected to said ground, said electrical resistance heating element comprising a coil of resistance wire coiled about a rod-like member constructed of dielectric material.

References Cited by the Examiner UNITED STATES PATENTS 990,249 4/11 Garcia 26 l142 1,246,727 11/ 17 Donning. 1,320,787 11/19 McElrath. 2,245,672 6/41 Hunt. 2,309,170 1/ 43 De Beaumont. 2,624,325 1/53 Fricke et al. 2,852,655 9/58 Viale.

HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner. 

1. IN A COMBINATION WITH AN INTERNAL COMBUSTION ENGINE INCLUDING AN EXHAUST MANIFOLD, AN INTAKE MANIFOLD, A CARBURETOR MOUNTED ON SAID INTAKE MANIFOLD AND PROVIDED WITH AN AUTOMATIC CHOKE ASSEMBLY ACTUATED BY MEANS OF A HEAT RESPONSIVE BIMETALLIC MEMBER ENCLOSED WITHIN A CASING INCLUDING AN INLET OPENING, AND A HEATED AIR CONDUCTIONG TUBE HAVING ONE END COMMUNICATED WITH SAID INLET OPENING, THE OTHER END OF SAID TUBE BEING OPEN AND DISPOSED IN GOOD HEAT TRANSFER RELATION WITH SAID EXHAUST MANIFOLD, A CHOKE ASSEMBLY HEATER ATTACHMENT COMPRISING A HOUSING HAVING AN INLET AND AN OUTLET AND DISPOSED IN SAID TUBE BETWEEN SAID CASING INLET AND SAID EXHAUST MANIFOLD, ELECTRICAL CONDUCTOR MEANS HAVING ONE END ELECTRICALLY CONNECTED TO ENGINE OPERATION RESPONSIVE SWITCH MEANS AND THE OTHER END ELECTRICALLY CONNECTED TO A SUITABLE GROUND, A PORTION OF SAID CONDUCTOR MEANS BEING DISPOSED IN SAID HOUSING AND AHVING AN ELECTRICAL RESISTANCE HEATING ELEMENT SERIALLY CONNECTED THEREIN, AND ADJUSTABLE THERMOSTATIC CONTROL SWITCH MEANS DISPOSED IN SAID PORTION OF SAID CONDUCTOR MEANS FOR CONTROLLING THE CIRCUIT DEFINED THEREBY AND CLOSING THE LATTER IN RESPONSE TO A DROP IN TEMPERATURE OF THE ATMOSPHERE WITHIN SAID HOUSING BELOW A PREDETERMINED LEVEL AND OPENING SAID CIRCUIT IN RESPONSE TO A RISE IN TEMPERATURE OF THE ATMOSPHERE WITHIN SAID HOUSING ABOVE A PREDETERMINED POINT ABOVE SAID PREDETERMINED LEVEL. 